In certain oilfield operations tools must be placed at a certain depth in a wellbore. In order to reach that depth, often tools must be conveyed downwell with the help of a pressurized medium, such as a pressurized fluid pumped from the surface, pumped behind the tool to help push the tool downwell. Such an operation can be known as a pumpdown operation. Tools can be supported from the surface by a line, such as a wireline, having a finite tensile strength.
During a pumpdown operation, there is a risk that tension may increase in the support line to an extent that the support line is damaged or completely severed (e.g., at a weakpoint where the support line attaches to the tool), known as pumpoff, which requires expensive and time-consuming remediation. Pumpoff can be avoided by regulation of pump pressure and support line feeding speed, each of which is managed by a human operator in a separate location. Each operator can be in vocal communication, such as through a telephone or radio. Due to the nature of wellbore interiors, operators may be required to react in a very short time frame (e.g., one to a few seconds), without much warning, in order to avoid pumpoff. Operators must react based only on the variables available to them, including pump pressure, surface tension, and support line feeding speed. Operators rely largely on experience to avoid pumpoff. With manual operator control, pumpoff risk remains substantial due at least in part to the restraints from human reaction times, human error, and the imprecision of manual control.